A spoonful of sugar helps the medicine go down but apparently the public will also happily accept movie tickets, cell phone minutes and discounts on air travel.

A private South African health plan, Discovery Health, increased patient use of preventive care using a program that incentivized healthy behavior using discounts on retail goods and travel.

"Even though most people know that preventive care is important, too few people take advantage of it," said Ateev Mehrotra, associate professor of health care policy at Harvard Medical School. "Incentive plans like this try to reinforce those long-term gains with more immediate rewards."

Encouraging the use of preventive care and healthy behaviors among patients is a core element of efforts to improve the quality and value of health care, including the Affordable Care Act. Learning how to encourage healthy behaviors is crucial for these efforts, but little is currently known about which incentive techniques work.

A few small-scale pilot programs and clinical trials have assessed the usefulness of incentives for efforts such as smoking cessation, but the long-term benefits of an incentive plan in real-world settings are not well understood. The plan in this study has been running for more than a decade with more than 1.5 million enrollees, providing ample data to study the impact of the plan on patient behaviors.

Over two-thirds of Discovery Health's enrollees have voluntarily chosen to pay approximately $15 per month to join the program. When program participants use preventive care measures, like blood pressure, glucose and cholesterol tests, they earn points that translate into discounts on retail goods and travel.

After joining the incentive plan, patient use of preventive services rose from 3 percent to 8 percent across a variety of services, the researchers found. These findings support the idea that patient incentive programs might be a mechanism for health plans to increase rates of preventive care, the researchers said.

South African participants in private health plans are similar demographically to the overall U.S. population and have similar access to health care. Such likeness makes this study a good model for considering parallel plans here in the U.S., the researchers said. Indeed, the same South African program is now being deployed by a U.S. health plan.

The increase in healthy behaviors was significant, Mehrotra noted, but even participants in the incentive program did not take advantage of the preventive measures available to them as often as medical guidelines recommend.

"There is no silver bullet in health care," Mehrotra said. "These types of incentive plans are not a panacea, but our findings suggest that they are a useful tool in encouraging the kinds of patient behavior that we would like to see more of."